SPOT is a 3D environment for direct sunlight visualization. Implemented in Java 3D, SPOT features two distinct and complementary components: Time Projection and Navigable Animation for virtual interaction. SPOT supports multi-dimensional data visualization including sun angle variations with diurnal and annual cycles in threedimensional space. In SPOT users can sketch on any surface in the 3D environment to indicate the area for simulation. SPOT then generates a spatial distribution representation of the illuminance level on a selected surface over time, rendered with colors of varied gradients. SPOT also enables designers to visualize the temporal information of light distribution over time for a given point. For each point clicked on the 3D model, SPOT generates a calendar diagram where the X and Y axis represent the months of the year and the time of the day. The color of each cell of the calendar is the result of the calculation of the light amount reaching the selected point.

Cohen, J., Hughes, J., and Zeleznik, R (2000) Harold: a world made of drawings
, ACM-Proceedings of the first international symposium on Non-photorealistic animation and rendering. SIGGRAPH & NPAR, pp. 83-90